Alan Pardew is convinced West Ham will "upset a few in Europe" - but first they must negotiate a way past tricky first round opponents Palermo.
Palermo finished eighth in last year's Serie A but were promoted to fourth place and direct qualification to the UEFA Cup following the Italian match-fixing scandal.
They opened this campaign on Sunday with a 4-3 victory over Reggina after a storming first half performance that sent jitters through West Ham's watching scouts Keith Peacock and Roger Cross.
But heading into the Hammers' first European campaign in seven years Pardew said: "If we could just get through this first two-legged tie I think we can make an impact, I really do. "This is the real tricky part of Europe for us. We will have had no experience (in Europe) and we have a lot of young guys who are going to be keen, maybe over-keen, to do well.
"If we get through I think with the way this team plays we can upset a few in Europe. But this tie is a big, big test for us."
The Hammers have struggled to find their attacking rhythm so far this season and Pardew knows it is vital they hit form again for tomorrow's home leg.
"The report that came back from Sunday's game was that if Palermo play like they did in that first half we shouldn't even bother turning up because they were that good," said Pardew
"The second half wasn't so good, so there is a little bit of hope for us, but it will be a tough game.
"We have got to try to push our philosophy on them because they are very good at playing the game at their speed. That will be a lot easier at home than it will away.
"They are a very good Serie A team and an outside tip for a Champions League place this season so we really are up against it.
"Their president said this could be the quarter-final but it is a qualifier (for the lucrative group stages). It is that tough for both teams.
"In some respects it's a no-lose situation for us."
That last comment in particular was unusual for Pardew, who has worked hard to encourage his young squad to attack teams without fear.